Data transmission apparatus and data reception apparatus

ABSTRACT

A data reception apparatus that includes a storage unit  263  for storing a direct directory message body specifying a data block identifier by the reference name, a key information selection unit  258  for obtaining the reference name, a reception unit  152  for receiving multiplexed data of indirect directory message blocks, data blocks, and the direct directory message body data, a separation unit  254  for separating the multiplexed data, a directly obtaining unit  264  for outputting the data block identifier using the direct directory message body, a selection unit  155  for outputting the identifier using indirect directory message bodies, a directory message body obtaining unit  156 , an indirect obtaining unit  257 , a data block selection unit  253  for selecting the data block according to the output identifier and for extracting a data file, a selection unit  261  for restoring and storing the direct directory message body, and a restoration unit  262 . When a direct directory message body includes a reference name, a data block identifier may be directly specified by the reference name without tracing indirect directory message bodies, and when a direct directory message body does not include a reference name, another direct directory message body is obtained and stored. As a result, the time for reception process is reduced.

FIELD OF THE INVENTION

The present invention relates to a data transmission apparatus and adata reception apparatus that transmits and receives a data file havinga directory structure, and especially relates to a method of effectivetransmission and reception of a plurality of data files that are to beused simultaneously or successively.

BACKGROUND OF THE INVENTION

FIG. 26 is a schematic diagram of a data transmission/reception system.

The data transmission/reception system shown in FIG. 26 includes abroadcasting station 901, a broadcasting satellite 902, a portableterminal 903, and a tabletop terminal 904.

Digital data in which a variety of kinds of data such as video, audio,and program information are multiplexed is transmitted over a broadcastwave from the broadcasting station 901. The broadcast wave carryingdigital data is relayed by the broadcasting satellite 902 and receivedby the portable terminal 903 and the tabletop terminal 904. From thereceived broadcast wave, desired data is extracted and used.

At present MPEG 2 (Moving Picture Coding Experts Group 2) transportstream is mainly used in the data transmission/reception system.

The MPEG 2 is standardized by the ISO/ICE13181. The object carousel(DSM-CC) standardized by the ISO/ICE 13181Extensions for DSM-CC definesthe control protocol of data download.

The DSM-CC standard defines a flow control method and a non-flow controlmethod. According to the flow control method, control information isefficiently transmitted and received. As a result, the flow controlmethod is suitable for local data transmission and reception but notsuitable for digital broadcasting data transmission and reception, bywhich the same data is transmitted to many receivers at one time. On theother hand, according to the non-flow control method, controlinformation does not transmitted from a receiver to a sender, so thatthe non-flow control method is suitable for the data transmission andreception as digital broadcasting.

The non-flow control method defined by the DSM-CC standard includes andata carousel transmission method (DSM-CC-UN) and an object carouseltransmission method (DSM-CC-UU). Here the data carousel transmissionmethod includes the object carousel transmission method.

In the data carousel transmission method, data to be transmitted iscyclically transmitted from the sender, and the receiver startsreceiving data with almost no wait. Note that the data carouseltransmission method is described in chapters 1 to 3 and 7 ofISO/ICE13181-6 in detail.

The object carousel transmission method is a data carousel transmissionsystem in which the standard is expanded as described below so that afile having a directory structure is transmitted.

1. Definition of BIOP Message

Data to be transmitted is independent by the module. Each of the modulesis composed of a plurality of BIOP messages.

FIG. 27 shows a module composed of a plurality of BIOP messages.

Four different object types, i.e., directory object, file object, streamobject, and service gateway (SGW), are defined as the BIOP message. Adirectory object includes the name of another object directly relatingto the directory corresponding to the directory object and theidentifier identifies the BIOP message corresponding to the object name.A file object includes file data or bitmap data. A stream objectincludes the reference to stream data that is transmitted bybroadcasting. It can be safely said that a service gateway is the sameas a directory object and is a particular directory object thatrepresents the root of a directory structure.

In this specification, the service gateway is considered a kind ofdirectory object and the stream object is considered a kind of fileobject in the interest of simplicity of the explanation of the presentinvention.

FIG. 28 shows the definition of directory object.

FIG. 29 shows the definition of file object.

2. Definition of IOP::IOR

FIG. 30 shows the definition of IOP::IOR.

A BIOP message includes an identifier IOP::IOR (referred to an“identifier IOR” in this specification) of a download ID, a module ID,and an object key in its own header. Each of the BIOP messages isidentified by the identifier IOR on the receiver side.

FIG. 31 shows the definition of BIOP::Object Location, which is animportant element of the identifier IOR in the object carouseltransmission method.

FIG. 32 is a schematic diagram of a conventional method for referring toa file message according to the name of the file (a key list) in theobject carousel transmission method.

Note that the data carousel transmission method is described in chapters2, 7, and 9 of ISO/ICE 13181-6, and the object carousel transmissionmethod is described in chapters 4, 5, and 11 of ISO/ICE13181-6.

Showing existing standards, FIGS. 26 to 32 are not explained in detailin this specification.

[Conventional Transmission Apparatus]

FIG. 33 shows the structure of a conventional transmission apparatus fortransmitting files having directory structures according to the objectcarousel transmission method.

A transmission apparatus 100 in FIG. 33 includes an indirect directorymessage block storage unit 101, an indirect directory message blockreading unit 102, a data block storage unit 103, a data block readingunit 104, a multiplexing unit 105, a data transmission unit 106, and anantenna 107.

The indirect directory message block storage unit 101 stores indirectdirectory message blocks. Note that an indirect directory message blockshows the names of the directories and files that directly relate to adirectory in the file structure.

The indirect directory message block reading unit 102 reads indirectdirectory message blocks from the indirect directory message blockstorage unit 101.

The data block storage unit 103 stores data blocks. Here, one data blockincludes one file.

The data block reading unit 104 reads data blocks from the data blockstorage unit 103.

The multiplexing unit 105 multiplexes the read indirect directorymessage blocks and the read data blocks into digital stream data. Morespecifically, the multiplexing unit 105 groups the read indirectdirectory message blocks and the read data blocks into a plurality ofmodules, gives a different module identifier to each of the modules,gives different object keys to the indirect directory message blocks anddata blocks in one module, and divides each of the modules into DDBs,i.e., units of transmission.

The data transmission unit 106 broadcasts the digital stream dataaccording to the object carousel transmission method via the antenna107.

[Conventional Reception Apparatus]

FIG. 34 shows the structure of a conventional reception apparatus thatreceives files having directory structures according to the objectcarousel method.

A reception apparatus 150 shown in FIG. 34 includes a reception antenna151, a data reception unit 152, a data block selection unit 153, a dataseparation unit 154, an indirect directory message block selection unit155, a directory message body obtaining unit 156, an identifier indirectobtaining unit 157, and a key information selection unit 158.

The data reception unit 152 receives data in the object carouseltransmission method that is being broadcasted via the reception antenna151, and restores digital stream data.

The data separation unit 154 extracts indirect directory message blocksand data blocks from the digital stream data. The data separation unit154 outputs the indirect directory message blocks to the indirectdirectory message block selection unit 155 and outputs the data blocksto the data block selection unit 154.

The key information selection unit 158 includes a key list buffer 159for temporarily storing a reference name that is input from a terminal“A”. The key information selection unit 158 selects directory names andfile names (keys) according to the name of the reference name that thekey list buffer 159 stores, and outputs the selected directory names andfile names to the identifier indirect obtaining unit 157. For instance,when the reference name is “˜/abc/def/ghi”, the key informationselection unit 158 selects four keys, in the order of “˜”, “abc”, “def”,and “ghi”. Note that a “˜” represents an “SGW(ServiceGateway)”, i.e.,the root of a directory structure and a “/” represents the difference oflevels.

The identifier indirect obtaining unit 157 selects an identifier IORrelating to the key that the key information selection unit 158 hasoutput from the indirect directory message body that the directorymessage body obtaining unit 156 has output, and outputs the identifierIOR to the indirect directory message block selection unit 155 and thedata block selection unit 154. Here, when the key is “˜”, no indirectdirectory message body has been output, so that the identifier IOR ofthe SGW is selected according to a method that is separately defined.Note that the method for selecting the identifier IOR of the SGW has noparticular bearing on the principle of the present invention, so thatthe selection method is not explained.

The indirect directory message block selection unit 155 selects thedirectory object corresponding to the identifier IOR that the identifierindirect obtaining unit 157 has output from the indirect directorymessage blocks that the data separation unit 154 has output, and outputsthe directory object to the directory message body obtaining unit 156.

The directory message body obtaining unit 156 obtains a BIOP::indirectDirectory Message Body in which partial reference names correspond todifferent identifiers IOR from the directory object, and outputs theBIOP::Directory Message Body to the identifier indirect obtaining unit157.

The data block selection Unit 153 selects a file object corresponding tothe identifier IOR that the identifier indirect obtaining unit 157 hasoutput from the data blocks that the data separation unit 154 hasoutput, and outputs the selected file object from a terminal “B”.

The reception apparatus 150 repeats the foregoing process every time areference name is input from the terminal “A” until a file object isoutput from the terminal “B” or the processes for all the keys arecompleted.

As has been described, in the conventional way of receiving files havingdirectory structures according to the carousel transmission method, itis necessary to repeat the reception of an indirect directory messageblock and the selection of a directory object the number of times of thedirectories in order to trace directories until the reception of atarget object. As a result, the process is complicated and the period oftime required to receive the target object is relatively long. Inaddition, data is repeatedly transmitted in cycle and the next cycle maybe waited for in the process, so that the period of time required toreceive the target object may be much longer and unstable.

One solution is proposed to shorten the receiving time. A plurality ofdata files that are likely to be received in succession (referred to“simultaneously-used-files” in this specification) is transmitted in thesame module, and the plurality of simultaneously-used-files are storedin a cache memory with the module when the module is reproduced toshorten the period of time from the reception of one data file to thereception of simultaneously-used-files.

FIG. 35 shows examples of transmitting simultaneously-used-files in onemodule.

In this method, however, directories still need to be traced. Inaddition, even when no simultaneously-used-file is stored in a cachememory, the data in the cache memory needs to be kept until the end ofthe tracing, so that the cache memory is not used effectively.

It is accordingly an object of the present invention to provide a datatransmission apparatus, a data reception apparatus, a data transmissionmethod, and a data reception method that effectively transmit andreceive a plurality of data files having directory structures to besimultaneously or successively used, a recording medium that stores thedata transmission method, and the data reception method, and a recordingmedium that stores transmission and reception data.

DISCLOSURE OF THE INVENTION

The data reception apparatus according to the present invention is adata reception apparatus that receives a file system having a directorystructure and obtains a data file corresponding to a reference namestarting from a predetermined directory name, wherein a data blockincludes a data file and an identifier of the data block, the datareception apparatus that may include: a storage unit for storing adirect directory message body that is used for directly specifying anidentifier of a data block corresponding to a reference name accordingto the reference name; a reference name obtaining unit for obtaining areference name of a data file to be obtained; a reception unit forreceiving multiplexed data into which a plurality of indirect directorymessage blocks, a plurality of data blocks, and data of at least onedirect directory message body have been multiplexed, an indirectdirectory message block includes an identifier of the indirect directorymessage block and an indirect directory message body that is used forspecifying an identifier of a data block corresponding to a data file ina first directory according to a name of the data file and is used forspecifying an identifier of an indirect directory message blockcorresponding to a second directory in the first directory according toa name of the second directory for each directory; a separation unit forextracting indirect directory message blocks, data blocks, and data ofdirect directory message body from the received multiplexed data andoutputting the extracted indirect directory message blocks, data blocks,and direct directory message body data; a direct reference unit foroutputting, when the direct directory message body stored by the storageunit includes the reference name that the reference name obtaining unithas obtained, a data block identifier that is directly specifiedaccording to the reference name according to the direct directorymessage body; a key information creation unit for separating, when thedirect directory message body stored by the storage unit does notinclude the reference name that the reference name obtaining unit hasobtained, a directory name and a file name in the reference name tocreate key information, and outputting the created key information; anindirect reference unit for outputting, when key information output bythe key information creation unit is a predetermined directory name, anidentifier of an indirect directory message block of the predetermineddirectory name; an indirect directory message block selection unit forselecting an indirect directory message block corresponding to the keyinformation from the indirect directory message blocks that theseparation unit has output according to the indirect directory messageblock identifier that the indirect reference unit has output; anindirect directory message body extraction unit for extracting anindirect directory message body from the selected indirect directorymessage block, wherein when the key information that has been output bythe key information creation unit is not a predetermined directory name,the indirect reference unit repeatedly retrieves an identifiercorresponding to the key information from the indirect directory messagebody that the indirect directory message body extraction unit hasextracted and outputs the retrieved identifier until a data blockidentifier is retrieved; a data block selection unit for selecting adata block corresponding to the key information from the data blocksthat the separation unit has output according to an identifier that oneof the direct reference unit and the indirect reference unit has outputand extracting a data file from the selected data block; a directdirectory message body selection unit for selecting data of a directdirectory message body corresponding to the data block from the data ofdirect directory message body that the separation unit has output; andan updating unit for storing the selected direct directory message bodydata in the storage unit.

As a result, when a direct directory message body includes a referencename, the identifier of a data block may be directly identified by thereference name, and when a direct directory message body includes noreference name, the identifier of a data block may be identified bytracing indirect directory message bodies and the direct directorymessage body may be obtained and stored for the data block that is to beselected later.

Since the direct directory message body for the second data block isstored when the first data block is selected, the identifier of thesecond data block may be identified directly by the reference namewithout tracing indirect directory message bodies when the second datablock is selected. As a result, the period of time required forreception is shortened.

The data reception apparatus according to the present invention may alsobe the data reception apparatus, wherein the reception unit receivesmultiplexed data into which information in a process before selection ofthe data block and direct directory message body data corresponding tothe data block have been multiplexed, and the direct directory messagebody selection unit selects the direct directory message body datacorresponding to the data block in the process before selection of thedata block.

As a result, the direct directory message body for the second data blockmay be obtained in the process of selecting the first data block, sothat the amount of work in the process of obtaining the direct directorymessage body data is reduced.

The data reception apparatus according to the present invention may alsobe the data reception apparatus, wherein direct directory message bodydata corresponding to a first data block is information that has beenmultiplexed into information in a process of selecting the first datablock and directly specifies an identifier of a second data blockaccording to a reference name of the second data block that is expectedto be successively selected after a selection of the first data block.

As a result, the direct directory message body data for the second datablock may be obtained in the process of selecting the first data block

The data reception apparatus according to the present invention may alsobe the data reception apparatus, wherein the direct directory messagebody data corresponding to the first data block for a module ismultiplexed into a stream that transmits the reproduction informationfor the module including the first data block, and when receiving thestream that transmits the reproduction information, the direct directorymessage body selection unit selects direct directory message body datacorresponding to the module from the stream.

As a result, the direct directory message body data for the second datablock may be obtained when the stream transmitting the reproductioninformation of the first data block is received.

The data reception apparatus according to the present invention may alsobe the data reception apparatus, wherein the direct directory messagebody data corresponding to the first data block is multiplexed into theindirect directory message block that has been selected by the indirectdirectory message block selection unit when the first data block isselected, and the direct directory message body selection unit selectsdirect directory message body data from the indirect directory messageblock that the indirect directory message block selection unit hasselected.

As a result, the direct directory message body data for the second datablock may be obtained when an indirect directory block is selected forselecting the first data block.

The data transmission apparatus according to the present invention is adata transmission apparatus that transmits a file system having adirectory structure that may include: an obtaining unit for obtaining aplurality of indirect directory message blocks, a plurality of datablocks, and at least one direct directory message body, an indirectdirectory message block includes an identifier of the indirect directorymessage block and an indirect directory message body that is used forspecifying an identifier of a data block corresponding to a data file ina first directory according to a name of the data file and is used forspecifying an identifier of an indirect directory message blockcorresponding to a second directory in the first directory according toa name of the second directory for each directory, a data block includesan identifier of the data block and a data file, a direct directorymessage body is used to directly specify an identifier of a data blockcorresponding to a reference name starting from a predetermineddirectory name; a multiplexing unit for multiplexing the obtainedindirect directory message blocks, the obtained data blocks, and data ofthe obtained direct directory message body, and creating multiplexeddata; and a transmission unit for transmitting the created multiplexeddata.

The data transmission apparatus transmits multiplexed data into which adirect directory message body has been multiplexed is transmitted, sothat the identifier of a data block may be directly identified by areference name in a data transmission apparatus that receives themultiplexed data.

As a result, the period of time required for transmission and receptionis shortened.

The data transmission apparatus according to the present invention mayalso be the data transmission apparatus, wherein a direct directorymessage body is information that is used to directly specify anidentifier of a data block corresponding to a reference name of a datafile according to the reference name for each of a plurality of datafiles that are expected to be simultaneously or successively obtained.

As a result, in the data reception apparatus, the identifiers of thecorresponding data blocks may be directly identified by the referencenames of a plurality of data files that are expected to besimultaneously or successively obtained, so that the identifiers of thedata blocks that are expected to be simultaneously or successivelyobtained may be identified once a direct directory message body isobtained.

The data transmission apparatus according to the present invention mayalso be the data transmission apparatus, wherein the multiplexing unitmultiplexes direct directory message body data into information used forspecifying a data block represented by a reference name in the directdirectory message body for each reference name in the direct directorymessage body.

As a result, in the data reception apparatus, the direct directorymessage body data for the second data block may be obtained in theprocess of selecting the first data block, so that the amount of work inthe process of obtaining the direct directory message body data isreduced.

The data transmission apparatus according to the present invention mayalso be the data transmission apparatus, wherein the multiplexing unitmultiplexes direct directory message body data into a stream used forspecifying a module represented by an identifier in the direct directorymessage body.

As a result, in the data reception apparatus, the direct directorymessage body data for the second data block may be obtained from thestream that has been reproduced in the process of selecting the firstdata block, so that the amount of work in the process of obtaining thedirect directory message body data is reduced.

The data transmission apparatus according to the present invention mayalso be the data transmission apparatus, wherein the multiplexing unitmultiplexes direct directory message body data into indirect directorymessage blocks used for specifying a data block represented by areference name in the direct directory message body for each referencename in the direct directory message body.

As a result, in the data reception apparatus, the direct directorymessage body data for the second data block may be obtained from theindirect directory message blocks that have been obtained in the processof selecting the first data block, so that the amount of work in theprocess of obtaining the direct directory message body data is reduced.

The data reception method according to the present invention is a datareception method for receiving a file system having a directorystructure and obtaining a data file corresponding to a reference namestarting from a predetermined directory name in a data receptionapparatus that includes storage unit for storing a direct directorymessage body used for directly specifying an identifier of a data blockcorresponding to the reference name according to the reference name, adata block includes a data file and an identifier of the data block, thedata reception method may include: a reference name obtaining step forobtaining a reference name of a data file to be obtained; a receptionstep for receiving multiplexed data into which a plurality of indirectdirectory message blocks, a plurality of data blocks, and data of atleast one direct directory message body have been multiplexed, anindirect directory message block includes an identifier of the indirectdirectory message block and an indirect directory message body that isused for specifying an identifier of a data block corresponding to adata file in a first directory according to a name of the data file andis used for specifying an identifier of an indirect directory messageblock corresponding to a second directory in the first directoryaccording to a name of the second directory for each directory; aseparation step for extracting indirect directory message blocks, datablocks, and data of direct directory message body from the receivedmultiplexed data and outputting the extracted indirect directory messageblocks, data blocks, and direct directory message body data; a directreference step for outputting, when the direct directory message bodystored in the storage unit includes the reference name that has beenobtained at the reference name obtaining step, a data block identifierthat is directly specified according to the reference name according tothe direct directory message body; a key information creation step forseparating, when the direct directory message body stored in the storageunit does not include the reference name that has been obtained at thereference name obtaining step, a directory name and a file name in thereference name to create key information, and outputting the created keyinformation; an indirect reference step for outputting, when keyinformation output at the key information creation step is apredetermined directory name, an identifier of an indirect directorymessage block of the predetermined directory name; an indirect directorymessage block selection step for selecting an indirect directory messageblock corresponding to the key information from the indirect directorymessage blocks that has been output at the separation step according tothe indirect directory message block identifier that has been output atthe indirect reference step; an indirect directory message bodyextraction step for extracting an indirect directory message body fromthe selected indirect directory message block, wherein when the keyinformation that has been output at the key information creation step isnot a predetermined directory name, an identifier corresponding to thekey information is repeatedly retrieved from the indirect directorymessage body that has been extracted at the indirect directory messagebody extraction step and the retrieved identifier is output until a datablock identifier is retrieved at the indirect reference step; a datablock selection step for selecting a data block corresponding to the keyinformation from the data blocks that has been output at the separationstep according to an identifier that has been output at one of thedirect reference step and the indirect reference step and extracting adata file from the selected data block; a direct directory message bodyselection step for selecting data of a direct directory message bodycorresponding to the data block from the data of direct directorymessage body that has been output at the separation step; and anupdating step for storing the selected direct directory message bodydata at the storage step.

As a result, when a direct directory message body includes a referencename, the identifier of a data block may be directly identified by thereference name, and when a direct directory message body includes noreference name, the identifier of a data block may be identified bytracing indirect directory message bodies and the direct directorymessage body may be obtained and stored for the data block that is to beselected later.

Since the direct directory message body for the second data block isstored when the first data block is selected, the identifier of thesecond data block may be identified directly by the reference namewithout tracing indirect directory message bodies when the second datablock is selected. As a result, the period of time required forreception is shortened.

The data transmission method according to the present invention is adata transmission method for transmitting a file system having adirectory structure that may include: an obtaining step for obtaining aplurality of indirect directory message blocks, a plurality of datablocks, and at least one direct directory message body, an indirectdirectory message block includes an identifier of the indirect directorymessage block and an indirect directory message body that is used forspecifying an identifier of a data block corresponding to a data file ina first directory according to a name of the data file and is used forspecifying an identifier of an indirect directory message blockcorresponding to a second directory in the first directory according toa name of the second directory for each directory, a data block includesan identifier of the data block and a data file, a direct directorymessage body is used to directly specify an identifier of a data blockcorresponding to a reference name starting from a predetermineddirectory name; a multiplexing step for multiplexing the obtainedindirect directory message blocks, the obtained data blocks, and data ofthe obtained direct directory message body, and creating multiplexeddata; and a transmission step for transmitting the created multiplexeddata.

The data transmission apparatus transmits multiplexed data into which adirect directory message body has been multiplexed is transmitted, sothat the identifier of a data block may be directly identified by areference name in a data transmission apparatus that receives themultiplexed data.

As a result, the period of time required for transmission and receptionis shortened.

The computer-readable recording medium according to the presentinvention that records a data reception program is a computer-readablerecording medium that records a data reception program for receiving afile system having a directory structure and for obtaining a data filecorresponding to a reference name starting from a predetermineddirectory name in a data reception apparatus that includes storage unitfor storing a direct directory message body directly specifying anidentifier of a data block corresponding to the reference name accordingto the reference name, a data block includes a data file and anidentifier of the data block, the data reception program has a computerexecute steps that may include: a reference name obtaining step forobtaining a reference name of a data file to be obtained; a receptionstep for receiving multiplexed data into which a plurality of indirectdirectory message blocks, a plurality of data blocks, and data of atleast one direct directory message body have been multiplexed, anindirect directory message block includes an identifier of the indirectdirectory message block and an indirect directory message body that isused for specifying an identifier of a data block corresponding to adata file in a first directory according to a name of the data file andis used for specifying an identifier of an indirect directory messageblock corresponding to a second directory in the first directoryaccording to a name of the second directory for each directory; aseparation step for extracting indirect directory message blocks, datablocks, and data of direct directory message body from the receivedmultiplexed data and outputting the extracted indirect directory messageblocks, data blocks, and direct directory message body data; a directreference step for outputting, when the direct directory message bodystored in the storage unit includes the reference name that has beenobtained at the reference name obtaining step, a data block identifierthat is directly specified according to the reference name according tothe direct directory message body; a key information creation step forseparating, when the direct directory message body stored in the storageunit does not include the reference name that has been obtained at thereference name obtaining step, a directory name and a file name in thereference name to create key information, and outputting the created keyinformation; an indirect reference step for outputting, when keyinformation output at the key information creation step is apredetermined directory name, an identifier of an indirect directorymessage block of the predetermined directory name; an indirect directorymessage block selection step for selecting an indirect directory messageblock corresponding to the key information from the indirect directorymessage blocks that has been output at the separation step according tothe indirect directory message block identifier that has been output atthe indirect reference step; an indirect directory message bodyextraction step for extracting an indirect directory message body fromthe selected indirect directory message block, wherein when the keyinformation that has been output at the key information creation step isnot a predetermined directory name, an identifier corresponding to thekey information is repeatedly retrieved from the indirect directorymessage body that has been extracted at the indirect directory messagebody extraction step and the retrieved identifier is output until a datablock identifier is retrieved at the indirect reference step; a datablock selection step for selecting a data block corresponding to the keyinformation from the data blocks that has been output at the separationstep according to an identifier that has been output at one of thedirect reference step and the indirect reference step and extracting adata file from the selected data block; a direct directory message bodyselection step for selecting data of a direct directory message bodycorresponding to the data block from the data of direct directorymessage body that has been output at the separation step; and anupdating step for storing the selected direct directory message bodydata at the storage step.

As a result, the same effect as the data reception method may beobtained.

The computer-readable recording medium according to the presentinvention that records a data transmission program is acomputer-readable recording medium that records a data transmissionprogram for transmitting a file system having a directory structure, thedata transmission program has a computer execute steps that may include:an obtaining step for obtaining a plurality of indirect directorymessage blocks, a plurality of data blocks, and at least one directdirectory message body, an indirect directory message block includes anidentifier of the indirect directory message block and an indirectdirectory message body that is used for specifying an identifier of adata block corresponding to a data file in a first directory accordingto a name of the data file and is used for specifying an identifier ofan indirect directory message block corresponding to a second directoryin the first directory according to a name of the second directory foreach directory a data block includes an identifier of the data block anda data file, a direct directory message body is used to directly specifyan identifier of a data block corresponding to a reference name startingfrom a predetermined directory name; a multiplexing step formultiplexing the obtained indirect directory message blocks, theobtained data blocks, and data of the obtained direct directory messagebody, and creating multiplexed data; and a transmission step fortransmitting the created multiplexed data.

As a result, the same effect as the data transmission method may beobtained.

The computer-readable recording medium according to the presentinvention that records transmission and reception data is acomputer-readable recording medium that records transmission andreception data for transmitting and receiving a file system having adirectory structure, the transmission and reception data beingcharacterized by multiplexing of (1) a plurality of indirect directorymessage blocks, an indirect directory message block includes anidentifier of the indirect directory message block and an indirectdirectory message body that is used for specifying an identifier of adata block corresponding to a data file in a first directory accordingto a name of the data file and is used for specifying an identifier ofan indirect directory message block corresponding to a second directoryin the first directory according to a name of the second directory foreach directory; (2) a plurality of data blocks, a data block includes adata file and an identifier of the data block; and (3) data of at leastone direct directory message body that is information used for directlyspecifying an identifier of a data block corresponding to a referencename starting from a predetermined directory name according to thereference name into the transmission and reception data.

A direct directory message body has been multiplexed into thetransmission and reception data, so that the identifier of a data blockmay be directly identified by a reference name in a data receptionapparatus that receives the transmission and reception data.

As a result, the period of time required for transmission and receptionis shortened.

The computer-readable recording medium according to the presentinvention that records transmission and reception data may also be thecomputer-readable recording medium, wherein direct directory messagebody data is information that has been multiplexed into information usedfor specifying the first data block and directly specifies an identifierof a second data block according to a reference name of the second datablock that is expected to be successively selected after a selection ofthe first data block.

The direct directory message body data is multiplexed into informationused for identifying the first data block, so that the direct directorymessage body data may be obtained for the second data block in theprocess of selecting the first data block in a data reception apparatusthat receives the transmission and reception data. As a result, theamount of work in the process of obtaining the direct directory messagebody data is reduced.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other objects, advantages and features of the invention willbecome apparent from the following description thereof taken inconjunction with the accompanying drawings which illustrate a specificembodiment of the invention. In the Drawings:

FIG. 1 shows the structure of a transmission apparatus according to thefirst embodiment of the present invention;

FIG. 2 shows an MHEG(ISO/IEC13522-5) program;

FIG. 3 shows the directory structure of three data files, “˜/display”,“˜/bitmap.png”, and “˜/media/audio.aif ”, which are simultaneously orsuccessively used in the MHEG program shown in FIG. 2, an SGW, and adirectory object, “˜/media”;

FIG. 4 shows the contents of objects;

FIG. 5 shows the contents of objects;

FIG. 6 shows a direct directory message body stored in the directdirectory message body storage unit 211;

FIG. 7 shows the definition of BIOP::ModuleInfo;

FIG. 8 shows a transmission format;

FIG. 9 shows a format “directDictionaryInfo” when the content of adirect directory message body is stored in the “userInfo”;

FIG. 10 is an example of a transmission format of the BIOP::ModuleInfointo which the “directDictionaryInfo” shown in FIG. 9 has been inserted;

FIG. 11 shows a DII that has been created according to a directdirectory message body;

FIG. 12 shows a DII that has been created according to a directdirectory message body;

FIG. 13 shows a DII that has been created according to a directdirectory message body;

FIG. 14 is a flowchart showing the processing of the digital datatransmission by the transmission apparatus 200 according to the firstembodiment;

FIG. 15 shows the structure of a reception apparatus according to thefirst embodiment of the present invention;

FIG. 16 is an internal view of the ModuleId1 and ModuleId2, which are tobe transmitted by the transmission apparatus 200;

FIG. 17 is a flowchart showing the processing of the reception of thefile object “˜/display” by the reception apparatus 250 according to thefirst embodiment;

FIG. 18 is a flowchart showing the processing of the reception of thebitmap data file object “˜/bitmap.png” by the reception apparatus 250according to the first embodiment after the reception of the file datafile object “˜/display”;

FIG. 19 shows the structure of a transmission apparatus according to thesecond embodiment;

FIG. 20 shows the definition of the BIOP::directDictionary, which isused in storing direct directory message body data in the “objectInfo”;

FIG. 21 shows a directory object into which the data of a directdirectory message body shown in FIG. 6 has been inserted;

FIG. 22 shows a directory object into which the data of a directdirectory message body shown in FIG. 6 has been inserted;

FIG. 23 is a flowchart showing the processing of the digital datatransmission by the transmission apparatus 300 according to the secondembodiment;

FIG. 24 shows the structure of a reception apparatus according to thesecond embodiment of the present invention;

FIG. 25 is a flowchart showing the processing of the reception of thefile data file object “˜/display” by the reception apparatus 350according to the second embodiment;

FIG. 26 is a schematic diagram of a data transmission/reception system;

FIG. 27 shows a module composed of a plurality of BIOP messages;

FIG. 28 shows the definition of directory object;

FIG. 29 shows the definition of file object;

FIG. 30 shows the definition of IOP::IOR;

FIG. 31 shows the definition of BIOP::Object Location, which is animportant element of the identifier IOR in the object carouseltransmission method;

FIG. 32 is a schematic diagram of a conventional method for referring toa file message according to a file name (a key list) in the objectcarousel transmission method;

FIG. 33 shows the structure of a conventional transmission apparatus fortransmitting files having directory structures according to the objectcarousel transmission method;

FIG. 34 shows the structure of a conventional reception apparatus thatreceives files having directory structures according to the objectcarousel method; and

FIG. 35 shows examples of simultaneously-used-files transmitted in onemodule.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The detailed explanation of the preferred embodiments of the presentinvention will be given below with reference to figures.

The First Embodiment

[Outline]

According to the first embodiment, when data having directory structuresis transmitted and received, the transmission side inserts a directdirectory message body, with which reception information is directlyobtained by the reference name of a data file that is to be secondlyreceived, into the stream in advance that is to be received in thereception process of another data file that is to be firstly received,the reception side extracts and holds the direct directory message bodyin the reception process of the firstly-received data file, and directlyobtains reception information by the reference name by referring to theheld direct directory message body without tracing directories whenreceiving the secondly-received data file. As a result, the period oftime required to receive the files is shortened as a whole.

[Structure of Transmission Apparatus]

FIG. 1 shows the structure of a transmission apparatus according to thefirst embodiment of the present invention.

A transmission apparatus 200 shown in FIG. 1 includes an indirectdirectory message block storage unit 101, an indirect directory messageblock reading unit 102, a data block storage unit 103, a data blockreading unit 104, a multiplexing unit 205, a data transmission unit 106,an antenna 107, a direct directory message body storage unit 211, adirect directory message body reading unit 212, and a direct directorymessage block creation unit 213.

Here, the elements having the same functions as in the conventionaltransmission apparatus 100 are given the same reference numbers and theexplanation of these elements will not be given below.

FIG. 2 shows an MHEG(ISO/IEC13522-5) program.

FIG. 3 shows the directory structure of three data files “˜/display”,“˜/bitmap.png”, and “˜/media/audio.aif”, which are simultaneously orsuccessively used in the MHEG program shown in FIG. 2, an SGW, and adirectory object “˜/media”.

Here, the SGW and the data files “˜/display” and “˜/bitmap.png” are aModuleId1, and the data file “˜/media/audio.aif” and the directoryobject “˜/media” are a ModuleId2 as shown in FIG. 3. It is predictedthat the transmission of the unit of module realizes effective receptionon the reception side. Each of the modules are given a different moduleidentification number. More specifically, the object key in each of themodules are “K0”, “K1”, “K2”, and the like. FIGS. 4 and 5 show thecontents of the objects.

The direct directory message body storage unit 211 stores directdirectory message bodies.

FIG. 6 shows a direct directory message body stored in the directdirectory message body storage unit 211. In a direct directory messagebody, module identification numbers correspond to different object keysfor a data files.

The direct directory message body reading unit 212 reads a directdirectory message body.

The direct directory message block creation unit 213 converts the formof the direct directory message body that the direct directory messagebody reading unit 212 has read, and creates a direct directory messageblock that may be multiplexed.

The multiplexing unit 205 multiplexes at least one indirect directorymessage block, data block, and direct directory message block intodigital stream data. More specifically, at least one read indirectdirectory message block, data block, and direct directory message blockare divided into a plurality of modules, and each of the modules aregiven a different module identification number. In one module, each ofthe BIOPs are given a different object key, and each of the modules isdivided into DDBs, i.e., transmission units.

A detailed explanation of how a direct directory message block iscreated and multiplexed will be given below.

Here, part of a DII of the DSM-CC-UN is used as a direct directorymessage block.

According to the DSM-CC standard, a DDI is a stream for transmitting thetransmission information on the modules.

An extended area ModuleInfoByte:MIB is defined in a DII, and aBIOP::ModuleInfo is defined in an MIB in the DSM-CC-UN that defines PIDsand the like for which DDB should be transmitted by module.

FIG. 7 shows the definition of BIOP::ModuleInfo. FIG. 8 shows thetransmission format of the BIOP::ModuleInfo.

As shown in FIG. 7, an area released for the user “userinfo” is definedin the BIOP::ModuleInfo.

In the present embodiment, the content of a direct directory messagebody is stored in the “userInfo”.

FIG. 9 shows a format “directDictionaryInfo” when the content of adirect directory message body is stored in the “userInfo”. The“fullname” in FIG. 9 represents the “reference name” shown in FIG. 6 inthe direct directory message body. As a result, the object key of a BIOPis directory obtained from the “reference name” by referring to the“directDictionaryInfo”.

FIG. 10 is an example of a transmission format of the BIOP::ModuleInfointo which the “directDictionaryInfo” shown in FIG. 9 has been inserted.

FIGS. 11, 12, and 13 show DIIs that have been created according to thedirect directory message body shown in FIG. 6 by the process in thepresent invention.

[Operations of Transmission Apparatus]

FIG. 14 is a flowchart showing the processing of the digital datatransmission by the transmission apparatus 200 according to the firstembodiment.

The operations by the transmission apparatus 200 will be described withreference to FIG. 14.

(1) The indirect directory message block reading unit 102 reads anindirect directory message block from the indirect directory messageblock storage unit 101, the data block reading unit 104 reads a datablock from the data block storage unit 103, and the direct directorymessage body reading unit 212 reads a direct directory message body fromthe direct directory message body storage unit 211 (Step S1).

(2) The direct directory message block creation unit 213 creates adirect directory message block according to the read direct directorymessage body (Step S2).

(3) The multiplexing unit 205 divides read indirect directory messageblocks, read data blocks, and created direct directory message blocksinto a plurality of modules. Each of the modules is given a differentidentification number. In one module, each of the BIOPs are given adifferent object key, and each of the modules is divided into DDBs,i.e., transmission units (Step S3).

(4) The data transmission unit 106 cyclically transmits the DDBs (StepS4).

When receiving a data file, a reception apparatus does not need to tracedirectories. The reception apparatus only needs to refer to the directdirectory message body corresponding to the received data file.

[Structure of Reception Apparatus]

FIG. 15 shows the structure of a reception apparatus according to thefirst embodiment of the present invention.

A reception apparatus 250 in FIG. 15 includes a reception antenna 151, adata reception unit 152, a data block selection unit 253, a dataseparation unit 254, an indirect directory message block selection unit155, a directory message body obtaining unit 156, an identifier indirectobtaining unit 257, a key information selection unit 258, a directdirectory message block selection unit 261, a direct directory messagebody restoration unit 262, a direct directory message body storage unit263, and an identifier directly obtaining unit 264.

Here, the elements having the same functions as in the conventionalreception apparatus 150 are given the same reference numbers and theexplanation of these elements will not be given below.

Note that the reception apparatus 250 receives digital stream datatransmitted from the transmission apparatus 200 that has been created bymultiplexing at least one direct directory message blocks, indirectdirectory message blocks, and data blocks.

The data separation unit 254 extract an indirect directory messageblock, a direct directory message block, and a data block from thedigital stream data, and outputs the indirect directory message block tothe indirect directory message block selection unit 155, a DII includingthe direct directory message block to the direct directory message blockselection unit, and the data block to the data block selection unit 253.Here, the direct directory message block is the “directDictionaryInfo”in an MIB in the DII.

The identifier indirect obtaining unit 257 selects the identifier IORcorresponding to a key that the key information selection unit 158 hasoutput from the indirect directory message body that the directorymessage body obtaining unit 156 has output, and outputs the identifierIOR to the direct directory message block selection unit 261, theindirect directory message block selection unit 155, and the data blockselection unit 253.

The direct directory message block selection unit 261 selects the MIB ofthe module identified by the identifier IOR that the identifier indirectobtaining unit 257 has output from the DII that the data separation unit154 has output, and output the identifier IOR and the selected MIB tothe direct directory message body restoration unit 262.

The direct directory message body restoration unit 262 extracts the“directDictionaryInfo” from the MIB that the direct directory messageblock selection unit 261 has output, and restores a direct directorymessage body according to the extracted “directDictionaryInfo”.

The direct directory message body storage unit 263 holds the restoreddirect directory message body. When one direct directory message body isheld and another direct directory message body is restored, the newlyrestored direct directory message body should be given priority, i.e.,the previously restored one is deleted and the newly restored one isheld.

The identifier directly obtaining unit 264 retrieves the reference namethat a key list buffer 259 stores from the direct directory message bodythat the direct directory message body storage unit 263 stores. Whenretrieving the reference name, the identifier directly obtaining unit264 creates an identifier IOR from the ModuleId and the object keycorresponding to the reference name, and outputs the created identifierIOR to the data block selection unit 253. When failing to retrieve thereference name, the identifier directly obtaining unit 264 informs theidentifier indirect obtaining unit 257 of the failure, and instructs theidentifier indirect obtaining unit 257 to perform the conventionalprocessing.

The data block selection unit 253 selects the file object correspondingto the identifier IOR that the identifier directly obtaining unit 264has output from the data block that the data separation unit 254 hasoutput, and outputs the selected file object from a terminal B.

[Operations of Reception Apparatus]

Here, the operations by the reception apparatus 250 is explained as anexample, where the reception apparatus 250 receives and executes theMHEG(ISO/IEC13522-5) program shown in FIG. 2.

FIG. 16 is an internal view of the ModuleId1 and ModuleId2, which are tobe transmitted by the transmission apparatus 200.

The reception apparatus 250 reads a file object “˜/display” to executethe MHEG program shown in FIG. 2.

FIG. 17 is a flowchart showing the processing of the reception of thefile object “˜/display” by the reception apparatus 250 according to thefirst embodiment.

The explanation of the processing will be given below.

(1) The identifier directly obtaining unit 264 tries to retrieve thereference name “˜/display” that the key list buffer 259 stores from thedirect directory message body that the direct directory message bodystorage unit 263 stores. At this point in time, however, no directdirectory message body is stored in the direct directory message bodystorage unit 263, so that the reference name is not retrieved. Theidentifier indirect obtaining unit 257 is informed of the failure ofretrieval, and is instructed to perform the conventional processing(Step S11).

(2) The identifier indirect obtaining unit 257 outputs the identifierIOR of the SGW to the direct directory message block selection unit 261,the indirect directory message block selection unit 155, and the datablock selection unit 253 according to the key “˜” that the keyinformation selection unit 158 has output (Step S12).

(3) The direct directory message block selection unit 261 that hasreceived the IOR of the SGW selects the MIB of the module identified bythe identifier IOR that the identifier indirect obtaining unit 257 hasoutput in the DII that the data separation unit 254 has output, andoutputs the identifier IOR and the MIB to the direct directory messagebody restoration unit 262 (Step S13).

(4) The ModuleId1 that is transmitted from the transmission apparatus200 includes the “SGW”, the “˜/display”, and the “˜/bitmap.png” as shownin FIG. 16. In addition, the direct directory message blocks regardingthe “˜/display” and the “˜/bitmap.png” are included in the“directDictionaryInfo” in the MIB in the corresponding DII as shown inFIG. 11. As a result, the direct directory message body restoration unit262 extracts the “directDictionaryInfo” from the MIB that the directdirectory message block selection unit 261 has output, and restores adirect directory message body according to the extracted“directDictionaryInfo”. The direct directory message body storage unit263 holds the restored direct directory message body (Step S14).

(5) The indirect directory message block 155 that has received theidentifier IOR of the SGW selects the directory object corresponding tothe identifier IOR that the identifier indirect obtaining unit 257 hasoutput from the indirect directory message block that the dataseparation unit 254 has output, and outputs the selected directoryobject to the directory message body obtaining unit 156 (Step S15).

(6) The identifier indirect obtaining unit 257 selects the identifierIOR corresponding to the key “display” that the key informationselection unit 258 has output from the indirect directory message bodythat the directory message body obtaining unit 156 has output, andoutputs the selected identifier IOR to the direct directory messageblock selection unit 261, the indirect directory message block selectionunit 155, and the data block selection unit 253 (Step S16).

(7) The data block selection unit 253 selects the file object“˜/display” corresponding to the identifier IOR that the identifierindirect obtaining unit 257 has output from the data block that the dataseparation unit 254 has output, and outputs the selected file objectfrom the terminal “B” (Step S17).

After Step S17, the execution of the MHEG program shown in FIG. 2proceeds, and the bitmap data file object “˜/bitmap/png” for drawing isread.

FIG. 18 is a flowchart showing the processing in receiving the bitmapdata file object “˜/bitmap.png” by the reception apparatus 250 accordingto the first embodiment after the reception of the file data file object“˜/display”.

The explanation of the operations in the processing will be given below.

(1) The identifier directly obtaining unit 264 tries to retrieve thereference name “˜/bitmap.png” that the key list buffer 259 stores fromthe direct directory message body that the direct directory message bodystorage unit 263 stores. At this point in time, the direct directorymessage body storage unit 263 stores the direct directory message body,so that the identifier directly obtaining unit 264 retrieves thereference name, creates an identifier IOR from the ModuleId and theobject key corresponding to the reference name “˜/bitmap.png”, andoutputs the created identifier IOR to the data block selection unit 253(Step S21).

(2) The data block selection unit 253 selects the file object“˜/bitmap.png” corresponding to the identifier IOR that the identifierdirectly obtaining unit 264 has output from the data block that the dataseparation unit 254 has output, and outputs the selected file objectfrom the terminal B (Step S22).

After Step S22, the execution of the MHEG program shown in FIG. 2proceeds, and the directory object “˜/media” is received as in the caseof the processing in FIG. 17. At the time of the reception, the directdirectory message body on the audio stream object “˜/media/audio.aif” isrestored and held. As in the case of the processing shown in FIG. 18,the audio stream object “˜/media/audio.aif” is received.

As has been described, according to the first embodiment, when a datafile is received, a direct directory message body on the correspondingsimultaneously-used-files is received, and when one of thesimultaneously-used-files is received following the received data file,the simultaneously-used-file is received by referring to the directdirectory message body without tracing directories. As a result, theperiod of time required to receive the files is shortened as a hole.

The Second Embodiment

[Outline]

The second embodiment of the present invention is the same as the firstembodiment in shortening the time in reception as a whole by inserting adirect directory message body on the transmission side and referring tothe direct directory message body on the reception side.

The second embodiment differs from the first embodiment in storing thedata of a direct directory message body in the “objectInfo” in theBIOP::Binding structure in a indirect directory message block. On theother hand, the direct directory message body data is stored in the MIB,i.e., part of the DII in the DSM-CC-UN in the first embodiment.

[Structure of Transmission Apparatus]

FIG. 19 shows the structure of a transmission apparatus according to thesecond embodiment.

A transmission apparatus 300 shown in FIG. 19 includes an indirectdirectory message block storage unit 101, an indirect directory messageblock reading unit 102, a data block storage unit 103, a data blockreading unit 104, a multiplexing unit 105, a data transmission unit 106,an antenna 107, a direct directory message body storage unit 211, adirect directory message body reading unit 212, and a direct directorymessage body insertion unit 311.

Here, the elements having the same functions as in the conventionaltransmission apparatus 100 and the transmission apparatus 200 in thefirst embodiment are given the same reference numbers and theexplanation of these elements will not be given below.

As shown in FIG. 28, the “objectInfo”, which may store the auxiliaryinformation on a directory object, is defined in the BIOP::Bindingstructure of the directory message in the DSM-CC. The data of a directdirectory message body is stored in the “objectInfo” and transmitted inthe second embodiment.

FIG. 20 shows the definition of the BIOP::directDictionary, which isused in storing direct directory message body data in the “objectInfo”.

The direct directory message body data shown in FIG. 20 is substantiallythe same as shown in FIG. 9 referred to in the first embodiment.

The direct directory message body insertion unit 311 inserts directdirectory message body data into the “objectInfo” in the BIOP::Bindingstructure in an indirect directory message block. For instance, thedirect directory message body insertion unit 311 inserts the directdirectory message body data shown in FIG. 6 into objects in FIGS. 4 and5, and creates the directory objects shown in FIGS. 21 and 22.

[Operations of Transmission Apparatus]

FIG. 23 is a flowchart showing the processing of the digital datatransmission by the transmission apparatus 300 according to the secondembodiment.

The operations by the transmission apparatus 300 will be described withreference to FIG. 23.

(1) The indirect directory message block reading unit 102 reads anindirect directory message block from the indirect directory messageblock storage unit 101, the data block reading unit 104 reads a datablock from the data block storage unit 103, and the direct directorymessage body reading unit 212 reads a direct directory message body fromthe direct directory message body storage unit 211 (Step S31).

(2) The direct directory message body insertion unit 311 inserts thedata of the direct directory message body into the “objectInfo” in theBIOP::Binding structure in the indirect directory message block (StepS32).

(3) The multiplexing unit 105 divides indirect directory message blocksinto which direct directory message bodies have been inserted and readdata blocks into a plurality of modules. Each of the modules is given adifferent identification number. In one module, each of the BIOPs aregiven a different object key, and each of the modules is divided intoDDBs, i.e., transmission units (Step S33).

(4) The data transmission unit 106 cyclically transmits the DDBs (StepS34).

When receiving a data file, the transmission apparatus 300 does not needto trace directories. The transmission apparatus 300 only needs to referto the direct directory message body corresponding to the data file.

[Structure of Reception Apparatus]

FIG. 24 shows the structure of a reception apparatus according to thesecond embodiment of the present invention.

A reception apparatus 350 in FIG. 24 includes a reception antenna 151, adata reception unit 152, a data block selection unit 253, a dataseparation unit 154, an indirect directory message block selection unit155, a directory message body obtaining unit 356, an identifier indirectobtaining unit 157, a key information selection unit 258, a directdirectory message body restoration unit 362, a direct directory messagebody storage unit 263, and an identifier directly obtaining unit 264.

Here, the elements having the same functions as in the conventionalreception apparatus 150 and the reception apparatus 250 in the firstembodiment are given the same reference numbers and the explanation ofthese elements will not be given below.

Note that the reception apparatus 350 receives digital stream datatransmitted from the transmission apparatus 300 that has been created bymultiplexing at least one indirect directory message blocks into whichdirect directory message body data has been inserted and data blocks.

The direct directory message body restoration unit 356 obtains anindirect directory message body into which direct directory message bodydata has been inserted from a directory object, outputs the indirectdirectory message body from which the direct directory message body datahas been removed to the identifier indirect obtaining unit 157, andoutputs the direct directory message body data to the direct directorymessage body restoration unit 362.

The direct directory message body restoration unit 362 obtains thedirect directory message body data that has been inserted into the“ObjectInfo” in the BIOP::Binding structure in the indirect directorymessage block, and restores the direct directory message body.

[Operations of Reception Apparatus]

Here, the operations by the reception apparatus 350 is explained as anexample, where the reception apparatus 350 receives and executes theMHEG(ISO/IEC13522-5) program shown in FIG. 2.

The reception apparatus 350 reads the file data file object “˜/display”to execute the MHEG program shown in FIG. 2.

FIG. 25 is a flowchart showing the processing of the reception of thefile data file object “˜/display” by the reception apparatus 350according to the second embodiment.

The explanation of the processing will be given below.

(1) The identifier directly obtaining unit 264 tries to retrieve thereference name “˜/display” that the key list buffer 259 stores from thedirect directory message body that the direct directory message bodystorage unit 263 stores. At this point in time, however, no directdirectory message body is stored in the direct directory message bodystorage unit 263, so that the reference name is not retrieved. Theidentifier indirect obtaining unit 257 is informed of the failure ofretrieval, and is instructed to perform the conventional processing(Step S41).

(2) The identifier indirect obtaining unit 157 outputs the identifierIOR of the SGW to the indirect directory message block selection unit155 and the data block selection unit 253 according to the key “˜” thatthe key information selection unit 258 has output (Step S42).

(3) The indirect directory message block 155 that has received theidentifier IOR of the SGW selects the directory object corresponding tothe identifier IOR that the identifier indirect obtaining unit 157 hasoutput from the indirect directory message block that the dataseparation unit 154 has output, and outputs the selected directoryobject to the directory message body obtaining unit 356 (Step S43).

(4) The directory message body obtaining unit 356 obtains the indirectdirectory message body into which direct directory message body has beeninserted, outputs the indirect directory message body from which thedirect directory message body has been removed to the identifierindirect obtaining unit 157, and outputs the direct directory messagebody to the direct directory message body restoration unit 362 (StepS44).

(5) As in the case of the first embodiment, the ModuleId1 that istransmitted from the transmission apparatus 300 includes the “SGW”, the“˜/display”, and the “˜/bitmap.png” as shown in FIG. 16. In addition,the direct directory message body data regarding the “˜/display” and the“˜/bitmap.png” are included in the corresponding “directInfo”s in theBIOP::Binding structure as shown in FIGS. 21 and 22. As a result, thedirect directory message body restoration unit 362 restores the directdirectory message body according to the direct directory message bodydata that the directory message body obtaining unit 356 has output. Thedirect directory message body storage unit 263 holds the restored directdirectory message body (Step S45).

(6) The identifier indirect obtaining unit 157 selects the identifierIOR corresponding to the key “display” that the key informationselection unit 258 has output from the indirect directory message bodythat the directory message body obtaining unit 356 has output, andoutputs the selected identifier IOR to the indirect directory messageblock selection unit 155 and the data block selection unit 253 (StepS46).

(7) The data block selection unit 253 selects the file object“˜/display” corresponding to the identifier IOR that the identifierindirect obtaining unit 157 has output from the data block that the dataseparation unit 154 has output, and outputs the selected file objectfrom the terminal “B”. (Step S47).

After Step S47, the execution of the MHEG program shown in FIG. 2proceeds, and the bitmap data file object “˜/bitmap/png” for drawing isread.

The explanation of the operations when the reception apparatus 350receives the bitmap data file object “˜/bitmap/png” after the receptionof the file data file object “˜/display” will not given since theoperations are the same as explained with reference to FIG. 18 in thefirst embodiment.

After the reception of the bitmap data “˜/bitmap/png”, the execution ofthe MHEG program shown in FIG. 2 proceeds, and the directory object“˜/media” is received as in the case of the processing in FIG. 25. Atthe time of the reception, the direct directory message body on theaudio stream object “˜/media/audio.aif” is restored and held. As in thecase of the processing shown in FIG. 18, the audio stream object“˜/media/audio.aif” is received.

As has been described, according to the second embodiment, when a datafile is received, a direct directory message body on the correspondingsimultaneously-used-files is received, and when one of thesimultaneously-used-files is received following the received data file,the simultaneously-used-file is received by referring to the directdirectory message body without tracing directories. As a result, theperiod of time required to receive the files is shortened as a whole.

While the direct directory message body has a list structure in thefirst and second embodiments, the direct directory message body may haveanother structure such as a table structure.

While the key used for the retrieval from a directory message body andthe object key in the identifier IOR are character strings in the firstand second embodiments, the key and the object key may be, for instance,numerical values.

While the direct directory message body data is inserted into the“directDictionaryInfo” in the MIB in the DII and is transmitted in thefirst embodiment, the direct directory message body data may be insertedinto, for instance, an independent private section, and be transmitted.

While the direct directory message body data is inserted into the“objectInfo” in the BIOP::Binding structure and is transmitted in thesecond embodiment, the direct directory message body data may beinserted into, for instance, the “objectInfo” in the “Message SubHeade”in the BIOP::Generic Object Message.

While each of the first and second embodiments has been explained ashardware such as a Logic IC, the first and second embodiments may berealized by software. The software is the object of production, use,assignment, import, and the proposal of assignment or lease as in thecase of an apparatus even when stored in a computer-readable recordingmedium such as a CD-ROM.

Although the present invention has been fully described by way ofexamples with reference to the accompanying drawings, it is to be notedthat various changes and modifications will be apparent to those skilledin the art. Therefore, unless such changes and modifications depart fromthe scope of the present invention, they should by construed as beingincluded therein.

INDUSTRIAL USE POSSIBILITY

The present invention may be applied to a transmission apparatus withwhich a variety of data such as movie data is transmitted frombroadcasting stations and a reception apparatus with which the userreceives the transmitted data. By doing so, data may be received in ashorter period of time than ever.

The present invention may be applied to other transmission and receptionof such as a ground wave aside from digital satellite broadcasting.

What is claimed is:
 1. A data reception apparatus that receives a filesystem having a directory structure and obtains a data filecorresponding to a reference name starting from a predetermineddirectory name, wherein a data block includes a data file and anidentifier of the data block, the data reception apparatus, comprising:storage means for storing a direct directory message body that is usedfor directly specifying an identifier of a data block corresponding to areference name according to the reference name; reference name obtainingmeans for obtaining a reference name of a data file to be obtained;reception means for receiving multiplexed data into which a plurality ofindirect directory message blocks, a plurality of data blocks, and dataof at least one direct directory message body have been multiplexed,each of the indirect directory message blocks including an identifier ofthe indirect directory message block and an indirect directory messagebody that is used for specifying an identifier of a data blockcorresponding to a data file belonging to a first directory according toa name of the data file and is used for specifying an identifier of anindirect directory message block corresponding to a second directorybelonging to the first directory according to a name of the seconddirectory for each directory; separation means for extracting indirectdirectory message blocks, data blocks, and data of direct directorymessage body from the received multiplexed data and outputting theextracted indirect directory message blocks, data blocks, and directdirectory message body data; direct reference means for outputting, whenthe direct directory message body stored by the storage means includesthe reference name that the reference name obtaining means has obtained,a data block identifier that is directly specified according to thereference name according to the direct directory message body; keyinformation creation means for separating, when the direct directorymessage body stored by the storage means does not include the referencename that the reference name obtaining means has obtained, a directoryname and a file name in the reference name to create key information,and outputting the created key information; indirect reference means foroutputting, when key information output by the key information creationmeans is a predetermined directory name, an identifier of an indirectdirectory message block of the predetermined directory name; indirectdirectory message block selection means for selecting an indirectdirectory message block corresponding to the key information from theindirect directory message blocks that the separation means has outputaccording to the indirect directory message block identifier that theindirect reference means has output; indirect directory message bodyextraction means for extracting an indirect directory message body fromthe selected indirect directory message block, wherein when the keyinformation that has been output by the key information creation meansis not a predetermined directory name, the indirect reference meansrepeatedly retrieves an identifier corresponding to the key informationfrom the indirect directory message body that the indirect directorymessage body extraction means has extracted and outputs the retrievedidentifier until a data block identifier is retrieved; data blockselection means for selecting a data block corresponding to the keyinformation from the data blocks that the separation means has outputaccording to an identifier that one of the direct reference means andthe indirect reference means has output and extracting a data file fromthe selected data block; direct directory message body selection meansfor selecting data of a direct directory message body corresponding tothe data block from the data of direct directory message body that theseparation means has output; and updating means for storing the selecteddirect directory message body data in the storage means.
 2. The datareception apparatus according to claim 1, wherein the reception meansreceives multiplexed data into which information in a process beforeselection of the data block,and direct directory message body datacorresponding to the data block have been multiplexed, and the directdirectory message body selection means selects the direct directorymessage body data corresponding to the data block in the process beforeselection of the data block.
 3. The data reception apparatus accordingto claim 2, wherein direct directory message body data corresponding toa first data block is information that has been multiplexed intoinformation in a process of selecting the first data block and directlyspecifies an identifier of a second data block according to a referencename of the second data block that is expected to be successivelyselected after a selection of the first data block.
 4. The datareception apparatus according to claim 3, wherein the direct directorymessage body data corresponding to the first data block for a module ismultiplexed into a stream that transmits the reproduction informationfor the module including the first data block, and when receiving thestream that transmits the reproduction information, the direct directorymessage body selection means selects direct directory message body datacorresponding to the module from the stream.
 5. The data receptionapparatus according to claim 3, wherein the direct directory messagebody data corresponding to the first data block is multiplexed into theindirect directory message block that has been selected by the indirectdirectory message block selection means when the first data block isselected, and the direct directory message body selection means selectsdirect directory message body data from the indirect directory messageblock that the indirect directory message block selection means hasselected.
 6. A data transmission apparatus that transmits a file systemhaving a directory structure, comprising: obtaining means for obtaininga plurality of indirect directory message blocks, a plurality of datablocks, and at least one direct directory message body, each of theindirect directory message blocks including an identifier of theindirect directory message block and an indirect directory message bodythat is used for specifying an identifier of a data block correspondingto a data file belonging to a first directory according to a name of thedata file and is used for specifying an identifier of an indirectdirectory message block corresponding to a second directory belonging tothe first directory according to a name of the second directory for eachdirectory, a data block includes an identifier of the data block and adata file, a direct directory message body is used to directly specifyan identifier of a data block corresponding to a reference name startingfrom a predetermined directory name; multiplexing means for multiplexingthe obtained indirect directory message blocks, the obtained datablocks, and data of the obtained direct directory message body, andcreating multiplexed data; and transmission means for transmitting thecreated multiplexed data.
 7. The data transmission apparatus accordingto claim 6, wherein a direct directory message body is information thatis used to directly specify an identifier of a data block correspondingto a reference name of a data file according to the reference name foreach of a plurality of data files that are expected to be simultaneouslyor successively obtained.
 8. The data transmission apparatus accordingto claim 7, wherein the multiplexing means multiplexes direct directorymessage body data into information used for specifying a data blockrepresented by a reference name in the direct directory message body foreach reference name in the direct directory message body.
 9. The datatransmission apparatus according to claim 8, wherein the multiplexingmeans multiplexes direct directory message body data into a stream usedfor specifying a module represented by an identifier in the directdirectory message body.
 10. The data transmission apparatus according toclaim 8, wherein the multiplexing means multiplexes direct directorymessage body data into indirect directory message blocks used forspecifying a data block represented by a reference name in the directdirectory message body for each reference name in the direct directorymessage body.
 11. A data reception method for receiving a file systemhaving a directory structure and obtaining a data file corresponding toa reference name starting from a predetermined directory name in a datareception apparatus that includes storage means for storing a directdirectory message body used for directly specifying an identifier of adata block corresponding to the reference name according to thereference name, a data block includes a data file and an identifier ofthe data block, the data reception method comprising: a reference nameobtaining step for obtaining a reference name of a data file to beobtained; a reception step for receiving multiplexed data into which aplurality of indirect directory message blocks, a plurality of datablocks, and data of at least one direct directory message body have beenmultiplexed, each of the indirect directory message blocks including anidentifier of the indirect directory message block and an indirectdirectory message body that is used for specifying an identifier of adata block corresponding to a data file belonging to a first directoryaccording to a name of the data file and is used for specifying anidentifier of an indirect directory message block corresponding to asecond directory belonging to the first directory according to a name ofthe second directory for each directory; a separation step forextracting indirect directory message blocks, data blocks, and data ofdirect directory message body from the received multiplexed data andoutputting the extracted indirect directory message blocks, data blocks,and direct directory message body data; a direct reference step foroutputting, when the direct directory message body stored in the storagemeans includes the reference name that has been obtained at thereference name obtaining step, a data block identifier that is directlyspecified according to the reference name according to the directdirectory message body; a key information creation step for separating,when the direct directory message body stored in the storage means doesnot include the reference name that has been obtained at the referencename obtaining step, a directory name and a file name in the referencename to create key information, and outputting the created keyinformation; an indirect reference step for outputting, when keyinformation output at the key information creation step is apredetermined directory name, an identifier of an indirect directorymessage block of the predetermined directory name; an indirect directorymessage block selection step for selecting an indirect directory messageblock corresponding to the key information from the indirect directorymessage blocks that has been output at the separation step according tothe indirect directory message block identifier that has been output atthe indirect reference step; an indirect directory message bodyextraction step for extracting an indirect directory message body fromthe selected indirect directory message block, wherein when the keyinformation that has been output at the key information creation step isnot a predetermined directory name, an identifier corresponding to thekey information is repeatedly retrieved from the indirect directorymessage body that has been extracted at the indirect directory messagebody extraction step and the retrieved identifier is output until a datablock identifier is retrieved at the indirect reference step; a datablock selection step for selecting a data block corresponding to the keyinformation from the data blocks that has been output at the separationstep according to an identifier that has been output at one of thedirect reference step and the indirect reference step and extracting adata file from the selected data block; a direct directory message bodyselection step for selecting data of a direct directory message bodycorresponding to the data block from the data of direct directorymessage body that has been output at the separation step; and anupdating step for storing the selected direct directory message bodydata at the storage step.
 12. A data transmission method fortransmitting a file system having a directory structure, comprising: anobtaining step for obtaining a plurality of indirect directory messageblocks, a plurality of data blocks, and at least one direct directorymessage body, each of the indirect directory message blocks including anidentifier of the indirect directory message block and an indirectdirectory message body that is used for specifying an identifier of adata block corresponding to a data file belonging to a first directoryaccording to a name of the data file and is used for specifying anidentifier of an indirect directory message block corresponding to asecond directory belonging to the first directory according to a name ofthe second directory for each directory, a data block includes anidentifier of the data block and a data file, a direct directory messagebody is used to directly specify an identifier of a data blockcorresponding to a reference name starting from a predetermineddirectory name; a multiplexing step for multiplexing the obtainedindirect directory message blocks, the obtained data blocks, and data ofthe obtained direct directory message body, and creating multiplexeddata; and a transmission step for transmitting the created multiplexeddata.
 13. A computer-readable recording medium that records a datareception program for receiving a file system having a directorystructure and for obtaining a data file corresponding to a referencename starting from a predetermined directory name in a data receptionapparatus that includes storage means for storing a direct directorymessage body directly specifying an identifier of a data blockcorresponding to the reference name according to the reference name, adata block includes a data file and an identifier of the data block, thedata reception program has a computer execute steps, comprising: areference name obtaining step for obtaining a reference name of a datafile to be obtained; a reception step for receiving multiplexed datainto which a plurality of indirect directory message blocks, a pluralityof data blocks, and data of at least one direct directory message bodyhave been multiplexed, each of the indirect directory message blocksincluding an identifier of the indirect directory message block and anindirect directory message body that is used for specifying anidentifier of a data block corresponding to a data file belonging to afirst directory according to a name of the data file and is used forspecifying an identifier of an indirect directory message blockcorresponding to a second directory belonging to the first directoryaccording to a name of the second directory for each directory; aseparation step for extracting indirect directory message blocks, datablocks, and data of direct directory message body from the receivedmultiplexed data and outputting the extracted indirect directory messageblocks, data blocks, and direct directory message body data; a directreference step for outputting, when the direct directory message bodystored in the storage means includes the reference name that has beenobtained at the reference name obtaining step, a data block identifierthat is directly specified according to the reference name according tothe direct directory message body; a key information creation step forseparating, when the direct directory message body stored in the storagemeans does not include the reference name that has been obtained at thereference name obtaining step, a directory name and a file name in thereference name to create key information, and outputting the created keyinformation; an indirect reference step for outputting, when keyinformation output at the key information creation step is apredetermined directory name, an identifier of an indirect directorymessage block of the predetermined directory name; an indirect directorymessage block selection step for selecting an indirect directory messageblock corresponding to the key information from the indirect directorymessage blocks that has been output at the separation step according tothe indirect directory message block identifier that has been output atthe indirect reference step; an indirect directory message bodyextraction step for extracting an indirect directory message body fromthe selected indirect directory message block, wherein when the keyinformation that has been output at the key information creation step isnot a predetermined directory name, an identifier corresponding to thekey information is repeatedly retrieved from the indirect directorymessage body that has been extracted at the indirect directory messagebody extraction step and the retrieved identifier is output until a datablock identifier is retrieved at the indirect reference step; a datablock selection step for selecting a data block corresponding to the keyinformation from the data blocks that has been output at the separationstep according to an identifier that has been output at one of thedirect reference step and the indirect reference step and extracting adata file from the selected data block; a direct directory message bodyselection step for selecting data of a direct directory message bodycorresponding to the data block from the data of direct directorymessage body that has been output at the separation step; and anupdating step for storing the selected direct directory message bodydata at the storage step.
 14. A computer-readable recording medium thatrecords a data transmission program for transmitting a file systemhaving a directory structure, the data transmission program has acomputer execute steps, comprising: an obtaining step for obtaining aplurality of indirect directory message blocks, a plurality of datablocks, and at least one direct directory message body, each of theindirect directory message blocks including an identifier of theindirect directory message block and an indirect directory message bodythat is used for specifying an identifier of a data block correspondingto a data file belonging to a first directory according to a name of thedata file and is used for specifying an identifier of an indirectdirectory message block corresponding to a second directory belonging tothe first directory according to a name of the second directory for eachdirectory, a data block includes an identifier of the data block and adata file, a direct directory message body is used to directly specifyan identifier of a data block corresponding to a reference name startingfrom a predetermined directory name; a multiplexing step formultiplexing the obtained indirect directory message blocks, theobtained data blocks, and data of the obtained direct directory messagebody, and creating multiplexed data; and a transmission step fortransmitting the created multiplexed data.
 15. A computer-readablerecording medium that records transmission and reception data fortransmitting and receiving a file system having a directory structure,the transmission and reception data being characterized by multiplexingof (1) a plurality of indirect directory message blocks, each of theindirect directory message blocks including an identifier of theindirect directory message block and an indirect directory message bodythat is used for specifying an identifier of a data block correspondingto a data file belonging to a first directory according to a name of thedata file and is used for specifying an identifier of an indirectdirectory message block corresponding to a second directory belonging tothe first directory according to a name of the second directory for eachdirectory; (2) a plurality of data blocks, each of the data blocksincluding a data file and an identifier of the data block; and (3) dataof at least one direct directory message body that is information usedfor directly specifying an identifier of a data block corresponding to areference name starting from a predetermined directory name according tothe reference name into the transmission and reception data.
 16. Thecomputer-readable recording medium according to claim 15, wherein directdirectory message body data is information that has been multiplexedinto information used for specifying the first data block and directlyspecifies an identifier of a second data block according to a referencename of the second data block that is expected to be successivelyselected after a selection of the first data block.